A Voltammetric Sensor Based on Multiwalled Carbon Nanotubes and a New Azoferrocene Derivative for Determination of Glutathione

A new azoferrocene derivative N-4,4´-azodianiline (ferrocenyl Schiff base) (ADAF, [Fe(cp)(azcp)]), was synthesized by reaction of ferrocene carbaldehyde and 4,4´-azodianiline in n-hexane. Then, a novel multiwalled carbon nanotubes/ carbon-paste modified electrode using ADAF was fabricated for the electrocatalytic determination of glutathione (GSH) in hemolysed erythrocyte. The measurements were carried out by the application of differential pulse voltammetry, cyclic voltammetry, and chronoamperometry. It was found that under the optimum conditions (pH = 6), the oxidation of GSH occurs at a potential about +0.52 V less positive than for the unmodified carbon-paste electrode. The electron-transfer coefficient (α) and rate constant for the chemical reaction between GSH and redox sites in the modified electrode were found to be 0.36 and 4.8 × 10⁵ cm³ mol^-1 s^-1, respectively. The catalytic peak current was linearly dependent on the GSH concentration in the range of 0.3-3350 μm with a detection limit of 0.08 μm. The proposed method was applied for the highly sensitive determination of GSH in hemolysed erythrocyte using the standard addition method.